Hi, Henk. Cool - so sort of the complement of what I am considering doing - your interface allows connection of a real device to a simulated hardware processor.
Your thorough documentation will be helpful in confirming the signals I plan to use. JRJ On 3/11/2019 1:39 PM, Henk Gooijen wrote: > Hi Jay, > > Have a look at www.pdp-11.nl/peripherals/tape/pc05-simh-pc.html > <http://www.pdp-11.nl/peripherals/tape/pc05-simh-pc.html> > > If you are interested I can tell you more … > > > > I can read and punch tape. PC05 + interface (PIC 18F4550) connects using > RX/TX to USB to PC. > > Reading one character at a time works fine (speed some 20 char/sec, > so-called start-stop mode). > > Reading in “streaming mode” is probably some 300 char/sec, but I get > unexplained “out-of-paper” state sometimes, and reading stops (of course). > > > > To read from the PC05 reader you need IOP2, IOP4, and INT*. Maybe BUSY* > is needed, not sure about that. > > INITIALIZE* is good to have as well. A few other signals (for example > IOP1) needs to be connected to an appropriate level. And 8 data inputs, > which need a pull-up resistor. Note that the data from the reader is > inverted. > > > > To punch you only need IOP4 (IIRC) and of course 8 data outputs. > > As you know, reader and punch are two completely isolated devices. > > > > Greetz, > > Henk > > > > > > ------------------------------------------------------------------------ > *Van:* cctech <cctech-boun...@classiccmp.org> namens Jay Jaeger via > cctech <cct...@classiccmp.org> > *Verzonden:* Monday, March 11, 2019 7:11:46 PM > *Aan:* General Discussion: On-Topic Posts > *Onderwerp:* Thinking about PDP11 PC05 Emulation > > I have several PDP-11's in my collection (among other things), and not > enough PC05 tape readers (or enough room) to go around. But most if not > all of my machines have M7810 PC11 interfaces, and I have one I could > move from machine to machine as needed. Moving a PC05 around would be a > lot more work, and not every rack has room. ;) > > So, I took a look at what it might take to interface with an M7810 (or, > down the road, a PDP-8/L or PDP-12. It looks like the emulator would > have to accept as input just 3 lines (Initialize L, IOP2(1)/Select, > IOP4(1)/Read) [It would not need the redundant Initialize H, IOP1(1), > Qualify or Skip], and would have to drive 11 lines into the pullups on > the M7810 (8 Data lines, IO Bus INT L/Reader Done L, Outtape/Error and > RDR RUN L/RDR Busy L). > > So, a total of 14 interface lines. (The 8 or 12 would take a few more > lines). > > The pullups average about 470 ohms (1 is 1K, 1 is 220, the rest are > 470), so at 5V the output has to sink a bit over 10ma, and all total > 120ma. > > An Arduino Uno with an Ethernet shield would have 20 minus 5 lines > available, in theory, but if one wants serial I/O as well for debugging, > that sucks up 2 more lines - so only 13 available. And sinking 120ma > would be a bit much though I could likely sprinkle inputs among the > outputs to make it work so as to stay within the recommended sink > limits, and at least initially have it never run out of tape, and tie > Error down. > > http://playground.arduino.cc/Main/ArduinoPinCurrentLimitations > > So, I am thinking about an Arduino Mega, as it has more output groupings > to sprinkle the sink current around, and 5V interface capability, and > more pins to eventually support my PDP-8/L and PDP-12. > > (I could do it with a PIC - did that for a Documation card reader to PC > interface, but I am really tired of fighting Microchip's IDE.) > > BUT - it also occurs to me someone may have already done something like > this? Any leads / ideas? > > JRJ
